Mix, knead, form and bake - a series of production techniques is the core technology for NGK, which conducts research and development based on the ceramic technology. We are under development of a manufacturing process, which realizes low cost, high quality and quick delivery and accommodates to diversifying products, from large insulators exceeding 10 meters in length to micro-scale ceramics.
Mixing materials or liquid plays an important role in manufacturing ceramic products as it has great influence on the quality. NGK works on selecting crushing methods and dispersion materials suitable for the raw materials as well as doing research on optimum conditions for mixing/kneading such as thermal control. The key to succeed in a kneading process is to knead the ceramic mixture soft enough to be able to change its form along the shape of the mold, and at the same time hard enough to be able to maintain its shape after forming. NGK's experts used to achieve the optimal hardness with their expertise, but now the company is taking a scientific approach exploiting technologies such as rheological measurement.
There are various methods of forming ceramics including extrusion, injection, pressing and casting, which are selectively used depending on the quality and shape of products. In response to diversifying products and higher performance, development of more advanced techniques capable of forming complicated shapes is now under way.
Firing is a process characteristic of ceramics production. With the aim of creating a product that have the properties we intended, NGK is working on finding conditions including firing temperature and the rate of a temperature rise suitable for each product, and establishing technologies that realize such conditions. Our recently focused project is development of firing facilities with less environmental impact.
It is almost impossible to ship unprocessed ceramics, which have just went through firing process, as products because they are subject to expansion and contraction and quality changes in the surface. Exercising processing techniques such as grinding and polishing, which we have learned from our long experience, NGK are creating high-precision products in micro- and recently nano-scale.